With rapid development of mobile communications technologies, functions of terminal products become diversified and complicated, posing increasingly stringent requirements on terminal antennas. Nowadays, an integration level of terminal products is continuously improved, which requires that the second generation mobile communications technology (2G), the third generation mobile communications technology (3G), and the fourth generation mobile communications technology (4G), that is, Long Term Evolution (LTE), are implemented in a same terminal product at the same time, posing increasingly high requirements on bandwidth and performance of an antenna. Therefore, antennas with wide frequency bands and high efficiency are needed to meet requirements of terminal products.
Currently, 4G LTE products have been commercially used, and some terminal products also start to be required to support an LTE frequency band. Because bandwidth of the LTE frequency band (for example, 791 megahertz (MHz) to 960 MHz, 1400 MHz to 1500 MHz, or 1710 MHz to 2690 MHz) is much wider than that of the previous 2G and 3G frequency bands, conventional antennas can hardly meet the bandwidth requirement. Moreover, it is required by the LTE that efficiency of antennas cannot be too low (for example, at least 35% for a low frequency, and at least 45% for a high frequency).
Therefore, how to implement an antenna that can cover an entire LTE frequency band and has high efficiency is an urgent technical problem that a person skilled in the art needs to resolve.